class Person:
    __id_number = '123123'  # 私有属性不能被继承

    def __init__(self, name):
        self.name = name

    def greet(self):
        print(f"hello i am {self.name}")


class Student(Person):
    """单继承"""

    def __init__(self, name, stu_id):
        super().__init__(name)
        self.stu_id = stu_id

    def show_stu_info(self):
        print(f'姓名：{self.name} 学号：{self.stu_id}')


stu1 = Student('张三')
stu1.greet()


